Speed-limiting device.



L. G. MARBURG.

SPEED LIMITING DEVICE. v APPLICATION FILED MAILQ, 1905.

Patented Mar. 11, 1913 EMx In uen [or Mfrzesses UNITED STATES PATENT OFFICE.

LOUIS C. MARBURG, OF NORWOOD, OHIO. ASSIGNOR TO THE BULLOCK ELECTRIC MANUFACTURING COMPANY A CORPORATION OF OHIO.

SPEED-LIMITING DEVICE.

Application filed March 9. 1905.

Specification of Letters Patent.

atcnted Mar. 11. 1913.

Serial No, 249.186.

To all whom if m (1 concern Be it known that l, LOUIS C, Mannvno, a citizen of the United States, residing at Nor wood, in the county of Hamilton and State of Ohio. have invented certain new and use ful Im movements in Speeddiimiting Dovices, (it which the following is a full, clear. and exact specification.

My invention relates to speed limiting devices as applied to rotating elements, and more particularly as applied to rotating members of dynamo electric machines of the rotary converter or motor generator type.

The invention is capable of use in connection with various types of machines, but is especially applicable to rotary converters, which as ordinarily employed in f \$i(ttl? of current t'listrihution, receive alternating cur rent from a source of supply and transform said alternating current into direct current, the latter being fed into a direct current distributing system. Under certain almormal conditions of field strength, load, and voltage, a compound wound rotary converter will run as an inverted rotary fed from the direct current mains, and will speed up to a dangerous extent. It is desirable under such circumstance to employ mean for automatically c ttting off the direct current source ofsupply from the machine controlling the current supplied to said machintn when its speed rises above a predetermined value.

As the periodicity, or frequency of alternations of current, in a circuit connected to an alternating current generator or source of supply is directly proportional to the speed of said generator. I take advantage of this fact in developing a speed limiting device for rotating shafts, or the rotatable elements of dynamo electric machines.

The object of my invention is therefore to develop a speed limiting device of this character which will he simple and inexpensive and one whichwill be positive in its action and will eliminate a danger resulting from the derangement of the circuit connections of a rotary converter.

My invention, therefore, consists in one of its aspects of the combination of a dynamo electric machine having a controlling device in the leads or maiuscoimected thereto, and a source of alternating current supply, the frequency of alternatimis of which depends upon the s )eed of said dynamo electric machine. and means connected with said alternating current source which is responsive to changes in the t'rta' ucncy of alternations in said source, said last mentioned means controlling the operation of said controlling device.

In another of its aspects my invention comprises the combination of a rotatable member. means for driving said member, means for controlling said driving means, a source of alternating current supply oper ated by said memhcn said controlling means being responsive to changes in the frequency of the alternating current of saiil source in such a manner that the driving means is rendered inoperative when the speed of the rotating member rises above a predetermined value.

The invention further comprises the combination of a rotary converter having direct. current mains and alternating current mains connected thereto with a controlling. device in the direct current mains, and means rcsponsive to changes in frequency of alternations in the alternating current mains controlling the operation of said circuit-brcakcr.

The invention will be more clearly understood by referring to the :u-companying drawings which illustrate the preferred em hodiments of my invention.

In said drawings, Figure 1 represents diagrammatically the circuit ctmuections of a rotary converter equipped with my improved speed limiting device; Fig. 2 represents diagrammatically a slightly modified form of said connections.

Referring now to 'he drawing the rotatable element the speed of which is to be limited is illustrated at 3. and in the specific arrangement shown. is thcshatt upon which the rotatable element 4 of a rotary converter is mounted. The direct current side ot' aid rotaryconverter is connected through the commutator 5 to the direct current llltlllh (3 and 7, and the alternating current ide of said rotary converter is connected through the. collector rings 8, 9, and I to the altcu hating current mains ll, 12. and 12, rcspcw tivelv. Viewing the invention in one of its bl' adcst a pct-ts, the direct current side of the rotary c nverter constitutes the means for driving the rotatable member 3 and the alternating current side of said rotary convertcr constitutes a source' t' alternating current supplyfllriven by said member. the

frequency of alternations of current from said source depending: upon the spcctl of said Iiieinher 3. mains is a controlling device. here shown a-- a circuit breaker 14, which may he of any ircuit Located in the dire t current type. The circuit breaker shown comprises 5 the fixed contacts 15 bridged by the inovable contact 16, which 1% prevented hy catch 18 from opening under the action (it spring:

17. This catch is under the control of over load coil 19 and the under-load or no voltage coil '20. The overload coil 1) acts directly upon the core 21, whilc the under load coil .20 acts upon the v aid core 2t through the weighted lever 22. pivoted at 23. The overload coil 19 is connected directly in the mains (3 and 7 and the under load coil 20 is connected in a shunt circuit '24 across said mains. Located in said shunt circuit 24 is a switch which under the control of a ditterentially wound magnet '25. said magnet having the coils 27 and 28, which act nor ially upon the core 29 in op position to each other. The two coils QT and 28 are located in parallel paths or divisions of a divided circuit connected to the alternating current source of supply. They may be connected directly across any pair of the alternating current mains ll, 12. and 13, but are preferably connected as shown in Fig. 1 to special brushes so and lit hearing against the collector rings 3 and 9 rcspectively on the alternating current sid of the rotary converter. To make the ditlcrentially wound magnet 26 responsive to changes in frequency of the current from said alternating current source of supply, but more or less independent of the voltage, I connect in circuit withthe coil 2% a reaotiance 32 and in circuit with the coil 27 a non-inductive resistance Under ordinary conditions of operation. with the frequency remaining. practically constant and the voltage varying, the differentially wound magnet 26 will permit the switch 25 to remain in its closed position. If, however, underabnormal conditions, the speed of the rotating member of the rotary converter rises above a predetermined value, the frequency of the alternating current generated in said rotary converter will iiicrease to such an extent that the current through the react ance coil 32 will be greatly retarded, while the current through thciion' inductive resistance 33 will not he rctardcd.

The result of this action is that the coil .37

will over-balance the coil 28 and will raise the core 29 against the action of gravity, or against the action of a spring, it a sprin,; is employed, sufficiently to open the switch and either directly open the shunt circuit 24. l

or insert the relatively high resistance 3i in said circuit. This cuts off or appreciably reduces the flow of current through the uiulcr-load coil 20, which in turn permits} the weighted lever 22 to drop and trip tlu. hrcaltcr. The system as shown is preferably so arranged that if the current rll'tligill in the direct current mains rises ahov a predetermined value. or the voltage falls below a minimum value, the circuit breaker will he opened automatically.

in the modification illustrated in Fig. the core 29 of the differentially wound magnet 26 instead of operating a switch for controlling the circuit breaker, acts directly upon the core 21 to trip the circuit. breaker at the pi'cdetcrniined soced.

The invention is capable of various inc-ditications and it is my aim in the appended claims to cover all modifications which do not. depart from the spirit of the invention.

Having thus described my invention, what. I claim as new and desire to secure by Lotters Patent is:-

1. 'In combination, a dynamo electric niachine, a' controlling device in the mains of said machine, a source of alternating current. the frequency of alternations of which depends upon the speed of said machine, a circuitconnected with said source, and a differentially \vound clcctroiiiagnet supplied from said circuit and having a reactauce connectcd in circuit with part of its winding so that the magnet will he responsive to the changes in frcquency of the alternating current of said source, and means for controlling the operation of said controlling device from said magnet. I

2. In combinatioma rotary converter having dircct. current mains and alternating current mains connected therewith, a con trcllinr device in the direct current mains and Qltt'lI't)ltl:|fllt'll(' means including a differentially wound magnet connected with the altcrnzitin z current side of said con \crtcr and I't'. l)tlll.-l\( to changes in frcquency of ihe current illlelflltt-llfllls in said alternating" cnrirnt sidc. said device controlline the opcratica of mid controlling device.

3. ln t 'llhlilllllilfill. a rotary converter hav ingtiil'tt'i cnrrcnt llHlllH and alternating current main connected therewith. controlling tit-vim 2?; the tlll'ttl current mains, a circuit t' nnccti-d to thialtcrnating current side of said t'tiil\ ci'tcl. a ditl'erentially '(Hllltl magnet in said circuit, a reactant-e in circuit with part of the magnet winding, and means ft r controlling the operation of said controlling dc'vicc from said magnet. 1

In conili nation, a rotary converter hav ing direct current mains and altcrnatin, current mains connected therewith. a c ir trolling! device in the direct current mains, a

circuit connected to the. alternating current 1 sid' of said converter a differentially wound magnet controlling said controlling device, and connected in said circuit, a reactant-e connected in circuit with part of the magnet winding. and a resistance con 1 nected in circuit with the remainder of the magnet winding, the whole being so constrncted and arranged that said controlling.

device will be operated when .the speed of the converter and hence the frequency of alternations of the alternating current rises above a predetermined value.

5. In combination, a rotatable member, means for driving said member, means for controlling said driving means, a source of alternating current operated by said member, a divided circuit connected to said source. a reactance in one branch of said circuit for changing the current in said branch on a change of frequency, and means responsive to a change of current in said branch for operating the controlling means.

(5. In combination. a rotatable member means for driving said member, a source 0 alternating current operated by said member, a circuit connected to said source of alternating current, and having two divi sicns or paths of different inductances, an elcctron'iagnetic device comprising two oppositely wound coils located in the respective divisions or paths of said circuit, and means controlled by said magnetic device to render said driving means inoperative when the frequency of alternating urrent from said source reaches a predetermined value.

7. In (minbination, a rotary converter having direct and alternating current mains connected thereto, a circnit-brc'aker in the direct current mains, a circuit connected to the alternating current mains, said circuit having two paths,means in one of said paths or divisions for changing the ratio of currents in said paths on a change of frequency, and means responsive to a change of the ratio ct currents in said paths for operating said circuit-breaker.

8. In combination, a rotary converter, hav

ing direct and alternating current mains connected thereto. a circuit-lu-eaker in the direct current mains, a circuit connected to the alternating current side of the converter and having two branches ot diiicrcnt inductances, and means responsive to a change in v the ratio between the currents in said two branches for causing the operation of said circuitdwcaltcr.

9. In combination, a rotary converter. a circuitbreaker in mains connected thereto. two paths for current from the alternating current side of the converter which are so proportioned that the ratio between the cur 1 l'tlll.\ carried thereby varies when the frequcncy of the impressed tltt'il'fllnfitlYt, force varies. and means rc.-p n1 ive lo a change in the ratio 'nciwccn the currents in said two path for ttllhlllQ thc operation oi said (ir cuit-bi-caln=r 10. In combination, a rotary converter, a

divided circuit connected to the alternating current side of said rotary converter, and electronmgnetically operated means controlled by currents in the branches of said circuit for causing the o eration of said circuit-breaker when the iiequency of the alternating current from said rotary converter rises above a predetermined value.

11. In combination, a rotary converter, a

a divided circuit connected to the alternating current side of said rotary converter, one of the branches of said circuit includinga device across which the drop of potential varies when the frequency of the alternating current from the rotary converter varies. said circuit including means responsive to the drop of potential across said device for causing the operation of said circuit-breaker.

12. A fre(piency-responsive device, co n prising, a. core, two coils connected in parallel paths and acting diametrically oppositely upon said core. an inductive resistance in circuit with said first coil, and an ohmic resistance in circuit with said second coil.

13. A frequency-rcsponsive device, conr prising a core, two coils acting diametrically oppositely on said core. and two parallel circuits in which said coils are respectively connccted and in which the impedance varies differently u )on change of frequency.

14. In com iination, an alternating current circuit. two coils supplied from said circuit hutlocated in different brancl'ies thereof, a rcactance in series with one of said coils, and a core upon which said coils act magnetically in opposite directions.

15. In combination. an alternating cur-- rent circuit, two coils sup )lied from said circuit but located in di ercnt branches thereof, a rcacl'ancc in series with one of said coil a core upon which said coils act magnetically in opposite directions, and a circnit'brcalu-r controlled by said core.

14'. In combination, an alternating cur-- rent circuit. two oils supplied from said circuit but located in dilicrcnt branches thereof. a ittl-"lzllltt in vseries with one of said t rolls. a ort: Hi which said coils act inag r ncticallv in opposite dir ctions. a direct cur rent circuit. and a circuitinvaltcr in said direct current cir u t and rontrollcd by said 1 core.

In testimony whereof I. atlix my signature, in the presence of two witnesses.

Invisc. MARIN no.

\Vitnesscs IiALricN-T Taiwan-acre, Tat-in J. Kivsrv.

circuit-breaker in mains connected thereto, a

circuitbreaker in mains connected thereto, 

